The Early Motor Questionnaire (EMQ): a parental report measure of early motor development

Children’s early motor skills are critical for development across language, social, and cognitive domains, and warrant close examination. However, examiner-administered motor assessments are time consuming and expensive. Parent-report questionnaires offer an efficient alternative, but validity of parent report is unclear and only few motor questionnaires exist. In this report, we use cross-sectional and longitudinal data to investigate the validity of parent report in comparison to two examiner-administered measures (Mullen Scales of Early Learning, MSEL; Peabody Developmental Motor Scales, PDMS-2), and introduce a new parent-report measure called the Early Motor Questionnaire (EMQ). Results indicate strong correlations between parent report on the EMQ and a child’s age, robust concurrent and predictive validity of parent report with both the MSEL and PDMS-2, and good test-retest reliability of parent report on the EMQ. Together, our findings support the conclusion that parents provide dependable accounts of early motor and cognitive development.

Keywords: Autism; Motor development; Parent report; Questionnaire.

Importance: The DSM-5 contains revised diagnostic criteria for autism spectrum disorder (ASD) from the DSM-IV-TR. Potential impacts of the new criteria on ASD prevalence are unclear.

Objective: To assess potential effects of the DSM-5 ASD criteria on ASD prevalence estimation by retrospectively applying the new criteria to population-based surveillance data collected for previous ASD prevalence estimation.

Design, setting, and participants: Cross-sectional, population-based ASD surveillance based on clinician review of coded behaviors documented in children’s medical and educational evaluations from 14 geographically defined areas in the United States participating in the Autism and Developmental Disabilities Monitoring (ADDM) Network in 2006 and 2008. This study included 8-year-old children living in ADDM Network study areas in 2006 or 2008, including 644 883 children under surveillance, of whom 6577 met surveillance ASD case status based on the DSM-IV-TR.

Main outcomes and measures: Proportion of children meeting ADDM Network ASD criteria based on the DSM-IV-TR who also met DSM-5 criteria; overall prevalence of ASD using DSM-5 criteria.

Results: Among the 6577 children classified by the ADDM Network as having ASD based on the DSM-IV-TR, 5339 (81.2%) met DSM-5 ASD criteria. This percentage was similar for boys and girls but higher for those with than without intellectual disability (86.6% and 72.5%, respectively; P < .001). A total of 304 children met DSM-5 ASD criteria but not current ADDM Network ASD case status. Based on these findings, ASD prevalence per 1000 for 2008 would have been 10.0 (95% CI, 9.6-10.3) using DSM-5 criteria compared with the reported prevalence based on DSM-IV-TR criteria of 11.3 (95% CI, 11.0-11.7).

Conclusions and relevance: Autism spectrum disorder prevalence estimates will likely be lower under DSM-5 than under DSM-IV-TR diagnostic criteria, although this effect could be tempered by future adaptation of diagnostic practices and documentation of behaviors to fit the new criteria.

The Early Autism Risk Longitudinal Investigation (EARLI), an ongoing study of a risk-enriched pregnancy cohort, examines genetic and environmental risk factors for autism spectrum disorders (ASDs). We simulated the potential effects of both measurement error (ME) in exposures and misclassification of ASD-related phenotype (assessed as Autism Observation Scale for Infants (AOSI) scores) on measures of association generated under this study design. We investigated the impact on the power to detect true associations with exposure and the false positive rate (FPR) for a non-causal correlate of exposure (X2, r=0.7) for continuous AOSI score (linear model) versus dichotomised AOSI (logistic regression) when the sample size (n), degree of ME in exposure, and strength of the expected (true) OR (eOR)) between exposure and AOSI varied. Exposure was a continuous variable in all linear models and dichotomised at one SD above the mean in logistic models. Simulations reveal complex patterns and suggest that: (1) There was attenuation of associations that increased with eOR and ME; (2) The FPR was considerable under many scenarios; and (3) The FPR has a complex dependence on the eOR, ME and model choice, but was greater for logistic models. The findings will stimulate work examining cost-effective strategies to reduce the impact of ME in realistic sample sizes and affirm the importance for EARLI of investment in biological samples that help precisely quantify a wide range of environmental exposures.

Keywords: Epidemiological Methods; MCH; Research Design in Epidemiology.

Keywords: autism spectrum conditions; sensory perception quotient; sensory questionnaire.